Music producer Phil Spector, left, stands in court with his attorney Roger Rosen during a status conference in his murder trial February 17, 2005.REUTERS

Nine board members worth billions have bolted from tarnished Bronx prep school Horace Mann as sex-abuse victims clamor for accountability in the wake of paltry settlement payouts as low as $20,000.

The exodus started last fall after a hard-line faction within the board reversed a tentative agreement to “do right by the victims” by conducting an internal investigation into decades of rampant sex abuse of more than 50 students by at least 20 teachers from the 1970s through the 1990s, multiple sources told The Post.

The hard-line charge was led by current board chairman Steven Friedman and recently promoted vice chairman Michael Colacino, sources said.

Beth Kobliner Shaw, whose hedge fund honcho husband David Shaw is worth $3.4 billion, is one of the most prominent board members who resigned.

Attorney Deborah C. Cogut also departed, but not without a fight to reveal the wrongs committed by the board of trustees. Cogut told The Post she asked to be relieved of the confidentiality agreement she had to sign when she joined the board 12 years ago, but the request was denied by the chairman.

Cogut, whose four boys attended the elite private school, has donated seven figures to Horace Mann over the years. Her husband, Craig Cogut, is the founder of Pegasus Capital, a private equity firm that manages $2.5 billion in assets.

Horace Mann also lost from its board some of the biggest names in New York City finance, including Daniel Shuchman, who manages computer pioneer Michael Dell’s $15 billion fortune, and the philanthropist/global fiscal guru Jamshid Ehsani.

“The school has alienated both trustees and former trustees and other major donors who would have gladly given money to help the victims,” said Joseph Cumming, a victim who runs the Web site HoraceMannSurvivor.org.

Departures continued in the spring with the exit of Goldman Sachs partner Jonathan M. Meltzer (class of 1983) and shopping center magnate Robert P. Heidenberg (class of 1976).

A school spokesman said “the 35 members of the board had a full and robust discussion of each of the matters, and as one might expect with that number of bright and sophisticated people, there were sometimes differing points of view.”

The spokesman acknowledged that four board members resigned last year over disagreements, but said that five departures this year “had nothing to do with disagreements” and left because of term limits and other issues.

Two sources, however, said the five who quit this year were upset because of the sex scandal.

Still, the spokesman also said that, after the board members left last fall, “virtually all” of the votes on the matter were unanimous.

Cumming is one of four victims who rebuffed settlement offers inked in March. He’s currently negotiating with the school on an agreement that will “satisfy his conscience.” Cumming was targeted by a serial molester, his music teacher and mentor Johannes Somary, for three years starting at age 15. Somary is now dead.

Based on conversations with victims and other sources close to the confidential settlements, Horace Mann paid out between $4 and $5 million to 27 former students. The highest figures were around $350,000 and the lowest $20,000. The average payout was $150,000.

“We got screwed again,” Ron Klepper bitterly joked to The Post. He agreed to speak openly about his deal without revealing the dollar figure. Klepper, 48, is an unemployed recovering heroin addict who says he has “no semblance of a normal life” because of the abuse that started at age 13.

“What the board did was give us a pittance for the damages we suffered,” Klepper said.

Another victim, who asked not to be identified so he could reveal details of his settlement, said he was “not content” with his payment, which was between $120,000 and $180,000 after a 30 percent cut for attorneys fees.

“It was in the highest echelons” of all the settlements, the man said.

“Many people were very hurt” by the amounts, he added. “Victims don’t want to feel like gold diggers, but there is fair compensation based on therapy bills and a person’s ability to be their best financial self.”

The biggest sums went to victims with the most egregious stories who were abused in the 1990s, and thus in the best position to challenge the statute of limitations.

But one of those victims never lived to see the compensation. Ben Balter killed himself in 2009 at age 32 after the school turned a blind eye to his family’s reports about Somary.

The money will go to his family, including mother and recently retired Horace Mann teacher Dr. Kathleen Howard. But Howard, 74, has yet to see a dime because the school is suing its insurance company to recoup the costs.

“The settlement payouts . . . don’t come close to compensating the victims for the horrendous abuse they endured during their formative years,” said attorney Rosemarie Arnold, who’s pursing a lawsuit in New Jersey against the school. “My client, who is one of the most severely abused, has shown tremendous courage in refusing to accept a pittance in exchange for his entitlement to justice and desire to hold those responsible for his torment fully accountable.”

Her client, who has not gone public about his abuse, was so disgusted by the settlement process that he stormed out of negotiations, a witness told The Post.

The man, yet another Somary victim, says he was molested 450 times by the creep in the 1970s. Arnold believes she has a strong case because New Jersey’s statute of limitations policy is more flexible.

Victims said the school could have avoided a lot of heartache if the board had agreed to the original proposition of abiding by its own anthem — “great is the truth and it prevails” — by investigating the history of abuse.

The former students who participated in the settlement talks with a mediator last March were aghast to learn the school prepared to rehash their personal accounts of abuse in a published report to answer demands for an accounting.

They had wanted school leadership to explain how the institution failed to protect its charges despite over a dozen reports throughout the years about widespread abuse.

“The board really wants to close the door on the school’s involvement,” said the victim who received a settlement in the mid $100s. “They want it hushed up.”

Indeed part of the settlement deal required victims to acknowledge Horace Mann’s denial that it “ever committed any wrongdoing” and absolve the pedophiles it allegedly harbored for years of potential future claims.

Cummings, the Horace Mann grad who runs the online community for fellow survivors, suspects the school is so adamantly opposed to an inward accounting because there are even more damning skeletons hidden in campus closets.

“When all the facts are known I think Horace Mann will make the Catholic Church look holy,” Cumming said.